In 2010, there were an estimated 250,000 AIDS related child deaths, and over 330,000 children newly infected with HIV in 2011, the majority in sub-Saharan Africa. With current, efficacious, low-cost medical interventions to prevent mother-to-child transmission of HIV (PMTCT), most of these infections were preventable. The continuing high rates of AIDS related child deaths demonstrate that scientifically rigorous implementation research is needed to successfully implement evidence-based interventions, like PMTCT, in resource-limited settings. Dr. Maria Kim, Assistant Professor in the Section of Retrovirology and Global Health at Baylor College of Medicine (BCM), is focused on closing this gap between knowledge and action by learning how to identify, research, and address implementation problems and thereby improve access to and use of interventions by women and children in need. Dr. Kim's research will evaluate how to optimize the implementation of Malawi's novel national PMTCT program Option B+ (B+). Other PMTCT approaches require HIV disease staging by clinical or lab criterion to distinguish between women who need life-long treatment for their own health versus those who only require short-term medication for PMTCT. In contrast, B+ offers all HIV-infected pregnant and breastfeeding women life-long antiretroviral treatment. Therefore, B+ theoretically provides a simplified approach, which may improve uptake, retention and transmission outcomes. However, there are no published studies evaluating its efficacy. A recent commentary in the Lancet highlighted the urgent need for more data about B+, before widely implementing in other countries. As a pediatrician in Malawi, Dr. Kim participated in a study that suggested inadequate coordination of maternal and infant HIV services was significantly contributing to >70% loss-to-follow-up in PMTCT care. Based on this data, she began a prospective open cohort study to examine the impact of a strategy called Tingathe, which utilizes community health workers (CHW) to help women navigate PMTCT care. In 2011, Dr. Kim analyzed 2 years of data on >1600 women-infant pairs which demonstrated improved retention to PMTCT care from <30% to ~75%, but still did not reach the target >90%. In September 2011, B+ was implemented in the context of this ongoing evaluation. Recent aggregate and field data from Malawi government and Tingathe program reports suggest that although uptake and retention has improved post B+, levels are still suboptimal. Additional patient level data are needed to build upon these reports. B+ has already been implemented widely throughout Malawi; thus, a randomized trial utilizing a control (non B+ sites) cannot be performed. However, Dr. Kim's cohort study provides a unique opportunity to evaluate B+ using patient level data, and Tingathe forms an implementation platform that can be modified to improve B+. In this IRSDA application, Dr. Kim proposes a three-prong study to both evaluate and optimize the implementation of B+. First, in Years 1 and 2 she will conduct a quasi-experimental pre/post study utilizing the prospectively collected longitudinal patient level data from the Tingathe program. Second, to better understand both implementation barriers and facilitators to optimizing PMTCT outcomes of B+ and the Tingathe strategy she will conduct a qualitative study using semi-structured 1:1 interviews of patients, health workers, and key informants engaging in PMTCT service uptake and delivery. Finally, starting in Year 3, she will design a modified CHW intervention informed by her previous studies, utilizing a community participatory approach and intervention mapping and design skills. The modified intervention will be tested for acceptability and feasibility in Years 4 and 5 using both qualitative and quantitative methods, in preparation for a proposed R01 funded randomized trial. Dr. Kim has assembled an outstanding mentorship team to help guide her research and career development. Dr. Peter Kazembe, the primary Malawi mentor, has over 30 years experience in child survival, malaria, and HIV research. He will be supported by Dr. Mina Hosseinipour, a former IRSDA recipient, Clinical Director of the University of North Carolina Malawi Project, and an expert in clinical and implementation trials in sub-Saharan Africa. Dr. Thomas Giordano, the primary US mentor, is an expert in health services research and will be supported by Drs. Christine Markham (mixed methods, intervention mapping and evaluation), Wenyaw Chan (biostatistics), Elizabeth Chiao (women's health, health services research), and Mary Paul (pediatric HIV). Co-mentor Dr Elaine Abrams, Senior Research Director of ICAP, and one of the foremost international authorities on PMTCT rounds out the mentorship team. With IRSDA support, Dr. Kim seeks to gain expertise in: 1) implementation research in resource- limited settings; 2) advanced study design and biostatistical methods; 3) qualitative research; 4) intervention design and evaluation; and 5) scientific writing and communication skills. To accomplish this she will complement her proposed research with structured tutorials and coursework and complete a Masters in Clinical Investigation through the Clinical Scientist Training Program at BCM. The unique Malawi research environment, supportive Malawi-US mentorship collaboration, and multi- disciplinary coursework will prepare Dr. Kim for independence as an implementation researcher by providing the skills, experience, and preliminary data to develop a R01 supported randomized trial evaluating the impact of a novel strategy to optimize the implementation of PMTCT.